172
CHAPTER 5. COASTAL STRUCTURE MODELS
The above list constitutes the most common types of structures used
in coastal engineering. Pile structures are not covered in this text because
it is a subject that has been exhaustively studied by the offshore industry
and suitably covered elsewhere. Soft structures, such as beach fills, also are
not discussed.
5.1.2
Purposes and Requirements of Structure Models
Markle (1989) listed five common purposes for conducting stability models
of rubble-mound structures. Markle’s list has been expanded below to cover
other types of coastal structures as well.
1. Examine the stability of rubble-mound armor layers protecting the slopes, toes, and/or crowns when exposed to
wave attack at different water levels. Studies can be aimed
at verifying specific designs or toward developing general
design guidance on armor sizes.
2. Determine the hydrodynamic forces exerted on monolithic
structures by wave action.
3. Optimize the structure type, size, and geometry to meet
performance requirements and budget constraints.
4. Investigate structure characteristics such as wave runup,
rundown, overtopping, reflection, transmission, absorption,
and static/dynamic internal pressures for different structure types, geometries, and/or construction methods.
5. Develop and/or test methods of repairing damage on existing structures or improving the performance of an existing
structure.
6. Determine the effects a proposed modification might have
on an existing structure’s stability and performance.
7. Examine alternate construction sequences under different
wave conditions. (See Hendry (1982) for an example of
construction sequence modeling for harbor breakwaters.)
Physical model tests directed at any of the above purposes will yield quantitative results provided the model is correctly scaled and operated, and
scale effects are determined to be minor.
Coastal structure physical models can be two-dimensional (2-d) or threedimensional (3-d). The more expensive 3-d models (Figure 5.1) are used to
obtain optimum positioning, length, height and alignment for a protective
CHAPTER 5. COASTAL STRUCTURE MODELS
The above list constitutes the most common types of structures used
in coastal engineering. Pile structures are not covered in this text because
it is a subject that has been exhaustively studied by the offshore industry
and suitably covered elsewhere. Soft structures, such as beach fills, also are
not discussed.
5.1.2
Purposes and Requirements of Structure Models
Markle (1989) listed five common purposes for conducting stability models
of rubble-mound structures. Markle’s list has been expanded below to cover
other types of coastal structures as well.
1. Examine the stability of rubble-mound armor layers protecting the slopes, toes, and/or crowns when exposed to
wave attack at different water levels. Studies can be aimed
at verifying specific designs or toward developing general
design guidance on armor sizes.
2. Determine the hydrodynamic forces exerted on monolithic
structures by wave action.
3. Optimize the structure type, size, and geometry to meet
performance requirements and budget constraints.
4. Investigate structure characteristics such as wave runup,
rundown, overtopping, reflection, transmission, absorption,
and static/dynamic internal pressures for different structure types, geometries, and/or construction methods.
5. Develop and/or test methods of repairing damage on existing structures or improving the performance of an existing
structure.
6. Determine the effects a proposed modification might have
on an existing structure’s stability and performance.
7. Examine alternate construction sequences under different
wave conditions. (See Hendry (1982) for an example of
construction sequence modeling for harbor breakwaters.)
Physical model tests directed at any of the above purposes will yield quantitative results provided the model is correctly scaled and operated, and
scale effects are determined to be minor.
Coastal structure physical models can be two-dimensional (2-d) or threedimensional (3-d). The more expensive 3-d models (Figure 5.1) are used to
obtain optimum positioning, length, height and alignment for a protective